Postselected amplification applied to atomic magnetometers

Abstract

We propose to embed the atomic magnetometer (AM) into an optical Mach-Zehnder interferometer (MZI). We analyze the effect of amplification of the Faraday rotation (FR) angle of the probe laser light, by properly postselecting the path-information state of the laser photons when passing through the MZI. In the presence of saturation of photo-detectors and existence of polarization cross talk in the polarizing-beam-splitter performance, the amplified FR angle in the postselected photons makes the scheme be able to outperform the conventional measurement (without postselection), being thus further enhancing the sensitivity of the nowadays state-of-the-art optical AM.